Introduction Noninvasive fetal heart rate monitoring using transabdominal fetal electrocardiographic detection is now commercially available and has been demonstrated to be an effective alternative to traditional Doppler ultrasonographic techniques. Our objective in this study was to compare the results of computerized identification of fetal heart rate patterns generated by ultrasound‐based and transabdominal fetal electrocardiogram‐based techniques with simultaneously obtained fetal scalp electrode‐derived heart rate information. Material and methods We applied an objective computer‐based analysis for recognition of fetal heart rate patterns (Monica Decision Support) to data obtained simultaneously from a direct fetal scalp electrode, Doppler ultrasound, and the abdominal‐fetal electrocardiogram techniques. This allowed us to compare over 145 hours of fetal heart rate patterns generated by the external devices with those derived from the scalp electrode in 30 term singleton uncomplicated pregnancies during labor. The direct fetal scalp electrode is considered to be the most accurate and reliable technique used in current clinical practice, and was, therefore, used as the standard for comparison. The program quantified the baseline heart rate, long‐ and short‐term variability. It indicated when an acceleration or deceleration was present and whether it was large or small. Results Ultrasound was associated with significantly greater deviations from the fetal scalp electrode results than the abdominal fetal electrocardiogram technique in recognizing the correct baseline heart rate, its variability, and the presence of small and large accelerations and small decelerations. For large decelerations the two external methods were each not significantly different from the scalp electrode results. Conclusions Noninvasive fetal heart rate monitoring using maternal abdominal wall electrodes to detect fetal cardiac activity more reliably reproduced the computerized analysis of heart rate patterns derived from a direct fetal scalp electrode than did traditional ultrasound‐based monitoring. Abdominal‐fetal electrocardiogram should, therefore, be considered a primary option for externally monitored patients.

Objective: To demonstrate a clear link between predicted blood shear forces during valve closure and thrombogenicity that explains the thrombogenic difference between tissue and mechanical valves and provides a practical metric to develop and refine prosthetic valve designs for reduced thrombogenicity. Methods: Pulsatile and quasi-steady flow systems were used for testing. The instantaneous valve flow area was measured using analog opto-electronics with output calibrated to the projected dynamic valve area. Flow velocity during the open and closing periods was determined from the instantaneous volumetric flow rate divided by valve flow area. For the closed valve interval, data obtained from quasi-steady back pressure/flow tests was used. Performance ranked by the derived valvular flow velocity and maximum negative closing flow velocity for all valves is experimental evidence for potential clinical thrombogenicity. Clinical, prototype and control valves were tested. Results: Establishment of a link between blood shear force and thrombogenicity led to optimization of a prototype mechanical bi-leaflet valve. The flow velocity metric was used to empirically design a 3-D printed model (BV3D) for softer valve closure dynamics which implicates reduced thrombogenic potential. Conclusions: The relationship between leaflet geometry, flow velocity and predicted shear at valve closure illuminated an important source of prosthetic valve thrombogenicity. With an appreciation for this relationship and based on our experiment generated comparative data, we achieved optimization of valve prototypes with potential for reduced thrombogenicity.